   ([[r g b] [x y z] [nx ny nz] angle concentration]
      (.spotLight *applet* r g b x y z nx ny nz angle concentration)))
 
-(defn sq [a] (PApplet/sq (float a)))
-
-(defn sqrt [a] (PApplet/sqrt (float a)))
+(defn sq
+  "Squares a number (multiplies a number by itself). The result is
+  always a positive number, as multiplying two negative numbers always
+  yields a positive result. For example, -1 * -1 = 1."
+  [a]
+  (PApplet/sq (float a)))
+
+(defn sqrt
+  "Calculates the square root of a number. The square root of a number
+  is always positive, even though there may be a valid negative
+  root. The square root s of number a is such that (= a (* s s)) . It
+  is the opposite of squaring."
+  [a]
+  (PApplet/sqrt (float a)))
 
 ;; $$start
 ;; $$status

  (PApplet/radians (float degrees)))

(defn random
  ([max] (.random *applet* (float max)))
  ([min max] (.random *applet* (float min) (float max))))


  []
  (PApplet/day))

(defn degrees
  "Converts a radian measurement to its corresponding value in
  degrees. Radians and degrees are two ways of measuring the same
  thing. There are 360 degrees in a circle and (* 2 Math/PI) radians
  in a circle. For example, (= 90° (/ Math/PI 2) 1.5707964). All
  trigonometric methods in Processing require their parameters to be
  specified in radians."
  [radians]
  (PApplet/degrees (float radians)))

(defn delay-frame [nap-time] (.delay *applet* (int nap-time)))

